Fuel-oil evaporation burners



Feb. 15, 1966 M. FISCHBACH FUEL-OIL EVAPORATION BURNERS Filed April 2, 1964 Inventor Min freal fils'ckbaal, y

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United States Patent 3,234,991 FUEL-OIL EVAPORATION BURNERS Manfred Fischbach, Altenbergstrasse 8, Neunkirchen, Kreis Siegen, Germany Filed Apr. 2, 1964, Ser. No. 356,907 Claims priority, application Germany, Apr. 9, 1963,

7 Claims. (a. 158-65) This invention relates to evaporation burners for fueloil, and more particularly to such burners in which the combustible mixture is formed in a burner bowl, to which the fuel and air are fed in the desired amounts. It has already been proposed in burners of this type to close the bowl by a burner head element which permits only annular gaps through which the mixture of fuel and air escapes from the bowl and consists of a cover plate, and spaced ring shaped disks which impart a predetermined length to the gaps in the direction of the fuel flow and are designed to ensure that combustion takes place only outside the bowl, that is to say to prevent the flame from backfiring into the bowl.

With such known burners difliculties are encountered in ensuring complete combustion and in regulation to within wide limits, even when the fuel and combustion air are fed under optimum conditions. The essential factor governing the complete combustion is that the temperature in the bowl must be high enough to evaporate rapidly the quantity of fuel corresponding to the maximum output of the burners. For this reason when using these burners it is essential for suflicient warmth to be transmitted from the flame to the bowl and first and foremost to the base of the bowl. In the known burners this warmth had to be transmitted over a long distance which led to difliculties where there were considerable burner outputs, especially when a multi-chambered system is necessary in the burner bowl. Burners of the known type must therefore be of sufficient dimensions that is to say, have heat-conductive sections of suflicient size if it is desired to achieve a noiseless flame without an excess of .air. Such burners however, are neither desirable or suitable for the normal heating apparatus. Likewise it is very difficult satisfactorily to regulate such burners as they are over-sensitive to alterations in the size of the flame. Their utility therefore is too limited to be commercially satisfactory.

The main object of the present invention is to provide a burner in which the said disadvantages are minimised.

According to the present invention a fuel oil evaporation burner comprises a burner bowl closed by a cover and having a hole in its base, an inlet aperture in the bowl wall through which fuel-oil and air enter the bowl, a wall surrounding the hole and provided with a gap between it and the bowl cover through which the fuel and air mixture pass to said hole, a burner head element having annular spaces therethrough mounted beneath the bowl, and a cover beneath the burner element with a wall at least partly surrounding said element, whereby air and oil enter the bowl, mix in the bowl after the oil evaporates therein, pass through said hole and said spaces in the element and burn on the outer portion of said element so that the burner flame warms the bowl to engender vaporisation of the oil in the bowl.

The burner of the invention has a bowl base which necessitates a high temperature to ensure evaporation of fueloil without leaving any trace of residual matter, since it is disposed in the flame which plays against it directly. In this way the bottom of the bowl can be raised to any desired temperature. In this connection cast-iron which is economical yet of low heat conductivity may be used as the heat is transmitted direct.

3,234,991 Patented Feb. 15, 1966 Cast-iron, in addition to lowering the cost of the burner also guarantees a longer life as the temperature necessary for evaporating the fuel-oil without trace, has no deleterious effect on cast-iron. A further advantage of the arrangement of the burner head beneath the burner bowl is that it is possible to adapt the burner solely by suitably adjusting the burner element disks without altering their shape or size, to various levels of heat required, excess air, speed of the gas, ignition speed, disintegration of the fuel mixture and total output of the burner. Whilst in the case of known burners the maxi mum output may not be altered without altering the dimensions of the bowl, such alteration is possible by the invention and results in considerable saving in cost when producing.

As the burner bowl is enveloped on the outside by the flame, the bowl can no longer be influenced by the temperature of the walls of the combustion chamber. As moreover, the flame emerges from beneath the bowl, the heating gases lap against practically the entire height of the combustion chamber so that the entire heating surface is uniformly subjected to the heat. In this manner there is uniformity in the loading of the heating surface which increases the thermal eificiency. The actual burner flame in this connection is short and hot. It is not necessary to embed the burner in fireclay muffles as in the case of diffusion burners. The short flame makes it possible to keep the firing chamber of the heated apparatus small. The conventional chimneyflue can also be dispensed with, which in turn makes it possible to reduce considerably the temperatures of the exhaust gases, thereby improving the thermal efiiciency considerably.

In a burner according to the invention the connections for the air feed are fitted on the burner bowl at the side. In this way the usual obstructing covers of the mixing chamber which necessitate an excess of air reducing the thermal efliciency are not required. Thus it is possible to use bellows to supply the air of combustion which produce less pressure and in consequence create less noise than conventionally required. The volume of air on the contrary is unlimited and burners can thus be made with higher outputs.

Whilst known burners can operate only in the on or off position burners of the invention may be variable in operation. The temperature of the hot water or the hot air of a heating unit can thus determine by means of a thermostat at which output the burner is to operate. The burner flame will not backfire inwards into the evaporation chamber of the bowl.

In order that the invention may be more clearly understood an embodiment in accordance therewith will now be described by way of example with reference to the accompanying drawing in which:

FIGURE 1 is a cross section through the burner; and

FIGURE 2 is a plan view of the bowl with the cover removed.

The burner bowl 1 has a bottom 2 and a jacket 3. The round and preferably cast-iron bowl is closed on top by a removable lid 4. A connection 5 is cast with the jacket 3 and a combustion air feed tube 6 and a fuel-oil feedpipe 7 are disposed therein. The open top of the connection 5 is closed by a removable lid 8. Electric supply leads 9 of electric heating elements 10 in the bowl base are accessible through the lid 8. The leads 9, electric ignition leads (not shown) are easily accessible and the burner flame inspection as well as other regulating operations may be easily carried out. The oil feed is completely protected in the air feed tube and the constant air circulation prevents the oil from solidifying in the tube and obstructing the oil feed pipe.

The oil feed pipe slopes downwardly so that when the burner is switched off it empties into the burner bowl. The end 11 of the tube 7 is formed as an open channel and is bent over at an obtuse angle to the wall 3 of the bowl, its open end being above a channel 12 in the evaporation surface 13 of the base 2. This has the advantage of preventing the oil in the tube 7 from evaporating and enables any vapour bubbles forming in it to escape freely. The channel 12 and the evaporating surface 13 themselves slope downwardly so that the oil continues to flow until it is finally evaporated. It was found that in this way the oil could be effectively prevented from solidifying in the channel. Also the channel can be disposed above the immediate influence of the burner flame. The end of the evaporation surface 13 is bounded by a baflle plate 14 which aids the mixing of the air and the oil vapour.

A hole 15 in the middle of the base 2 is surrounded by a flange 16 extending over its part 17 (bottom of FIGURE 2) almost up to the cover 4. The part 18 of the flange 16 (FIGURE 2) is not so high and in consequence leaves a gap 19 through which the mixture of air and fuel passes through the flange 16. The higher part 17 of the flange is joined to the wall 3 by a wall 20 lying obliquely to the direction in which the combustion air enters as it flows out of the connection 5. This air is compelled by the wall 20 and the flange 16 to move in an are round the vertical central axis of the bowl, before it can enter the hole 15 through the gap 19 between the lower part 18 of the flange and the lid 4. The oil vapour developed in the bowl is entrained by the combustion air, being mixed therewith.

A flange 21 is cast on to the bottom of the bowl 2, surrounding the hole 15. The burner head element is fitted on the flange beneath the bowl. This burner head element consists of a cover plate 22 designed in the shape of a cowl, that is to say it has a tapered wall 23 and several ring shaped disks 24 in spaced relationship to each other, so that gaps 25 are formed between these disks and the cover plate 22 through which the mixture of fuel flows out. The cover plate 22 and the disks 24 are secured to the flange 21 by several threaded bolts 26, distance pieces or wire lugs or nipples 27 being used to ensure that the disks are spaced from each other. The disks 24 may have profiled parts 28 on their inner periphery or they may be cylindrical.

The method of operation of the burner is as follows:

The combustion air is supplied to the burner from a bellows, through the pipe 6 and the fuel-oil is led by an oil regulator through the tube 7, the quantities of oil and air mixed being regulated by known means so that the optimum conditions of combustion are attained for every size of flame. Before the burner is put into operation the bottom 2 and its evaporating surface 13 are heated sufiiciently by the elements to cause the oil fed at the beginning to be immediately evaporated. The air as it enters mixes with the oil vapours. The mixture of fuel and air so formed then passes through the gap 19 in the flange 16 and passes through the hole in the base entering the burner head element, where it passes through the individual gaps 25 and emerges on the periphery of the disks 24. The gas as it emerges ignites on the outside of the disks in the characteristic cuniform shape peculair to a gas flame and the blue gas flame surrounding the cone, guided by the wall 23 burns upwards. The flame fiercely heats the evaporation surface 13 and also the wall 3 thereby ensuring the continued evaporation of the oil. The elements 10 can be switched off after the flame has ignited. By forming the surface 13 and also the wall 23 in a suitable manner and by adapting the diameter of the disks 24 with respect to the dimensions of the base of the bowl 2 it is possible to determine the necessary term perature level which prevents oil coke from collecting on the bottom of the bowl.

I claim:

1. A fuel evaporation burner comprising a burner bowl, a lid closing the bowl, an air and an oil inlet in the wall of the bowl, a base of the bowl having a hole therein, a wall surrounding said hole, a gap in said surrounding wall beneath said lid, a dividing wall and a baflle spaced therefrom dividing the chamber formed by the wall of the bowl and the surrounding wall to form an oil evaporation zone, a downwardly sloping channel in the outer periphery of the base of said chamber forming an evaporation surface, a burner head element mounted beneath the bowl and having annular spaces extending therethrough, a cover beneath said head element, and a wall surrounding said cover and at least part of said element, such that the oil evaporates in the bowl and mixing with the air passes through said gap, said hole and the spaces and burns on the outside of said element, the flame warming the bottom of the bowl to engender vaporisation of the fuel-oil therein.

2. A burner according to claim 1 wherein an oil supply pipe passes through the fuel-air inlet and has an open channel shaped end disposed above said channel towards the higher end thereof.

3. A burner according to claim 1 wherein the air-oil inlet comprises a chamber connected to the bowl and is covered by a lid.

4. A burner according to claim 1 wherein the baffle is mounted on the base of the bowl in the path of the air of combustion therethrough.

5. A fuel evaporation burner comprising a burner bowl, a lid closing the bowl, an air and an oil inlet in the wall of the bowl, a hole in the base of the bowl, a wall surrounding said hole, a gap in said surrounding wall beneath said lid, a dividing wall and a bafile spaced therefrom dividing the chamber formed by the wall of the bowl and the surrounding wall to form an oil evaporation zone, a downwardly sloping channel in the outer periphery of the base of said chamber forming an evaporation surface, a burner head element having a plurality of spaced superposed disks each with a profiled inner periphery mounted beneath the bowl, a cover beneath said head element and a wall surrounding said cover and at least part of said element, such that the oil evaporates in the bowl and mixing with the air passes through said gap, said hole and the spaces and burns on the outside of said element, the flame warming the bottom of the bowl to engender vaporisation of the fuel-oil therein.

6. A burner according to claim 5 wherein an annular flange is provided on the underside of the bowl and said burner head element is secured thereto.

7. A burner according to claim 5, in which said evaporation surface in the base of the bowl is thinner than the remaining parts of said base.

References Cited by the Examiner UNITED STATES PATENTS 499,720 6/1893 Darby 15863 2,058,652 10/1936 Wilson 158--53 2,069,960 2/1937 La Pointe.

2,445,302 7/1948 Clarkson. 2,458,630 1/1949 Palko.

3,035,633 5/1962 Palko 158-68 3,102,577 9/1963 Dekker 15866 FOREIGN PATENTS 526,089 7/1954 Belgium.

FREDERICK L. MATTESON, JR., Primary Examiner,

ROBERT A. DUA, Examiner. 

1. A FUEL EVAPORATION BURNER COMPRISING A BURNER BOWL, A LID CLOSING THE BOWL, AN AIR AND AN INLET IN THE WALL OF THE BOWL, A BASE OF THE BOWL HAVING A HOLE THEREIN, A WALL SURROUNDING SAID HOLE, A GAP IN SAID SURROUNDING WALL BENEATH SAID LID, A DIVIDING WALL AND A BAFFLE SPACED THEREFROM DIVIDING THE CHAMBER FORMED BY THE WALL OF THE BOWL AND THE SURROUNDING WALL TO FORM AN OIL EVAPORATION ZONE, A DOWNWARDLY SLOPING CHANNEL IN THE OUTER PERIPHERY OF THE BASE OF SAID CHAMBER FORMING AN EVAPORATION SURFACE, A BURNER HEAD ELEMENT MOUNTED BENEATH THE BOWL AND HAVING ANNULAR SPACES EXTENDING THERETHROUGH, A COVER BENEATH SAID HEAD ELEMENT, AND A WALL SURROUNDING SAID COVER AND AT LEAST PART OF SAID ELEMENT, SUCH THAT THE OIL EVAPORATES IN THE BOWL AND MIXING WITH THE AIR PASSES THROUGH SAID GAP, SAID HOLE AND THE SPACES AND BURNS ON THE OUTSIDE OF SAID ELEMENT, THE FLAME WARMING THE BOTTOM OF THE BOWL TO ENGENDER VAPORISATION OF THE FUEL-OIL THEREIN. 